Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
28,733
result(s) for
"Biological Phenomena"
Sort by:
Biological processes dominate seasonality of remotely sensed canopy greenness in an Amazon evergreen forest
Satellite observations of Amazon forests show seasonal and interannual variations, but the underlying biological processes remain debated.
Here we combined radiative transfer models (RTMs) with field observations of Amazon forest leaf and canopy characteristics to test three hypotheses for satellite-observed canopy reflectance seasonality: seasonal changes in leaf area index, in canopy-surface leafless crown fraction and/or in leaf demography.
Canopy RTMs (PROSAIL and FLiES), driven by these three factors combined, simulated satellite-observed seasonal patterns well, explaining c. 70% of the variability in a key reflectance-based vegetation index (MAIAC EVI, which removes artifacts that would otherwise arise from clouds/aerosols and sun–sensor geometry). Leaf area index, leafless crown fraction and leaf demography independently accounted for 1, 33 and 66% of FLiES-simulated EVI seasonality, respectively. These factors also strongly influenced modeled near-infrared (NIR) reflectance, explaining why both modeled and observed EVI, which is especially sensitive to NIR, captures canopy seasonal dynamics well.
Our improved analysis of canopy-scale biophysics rules out satellite artifacts as significant causes of satellite-observed seasonal patterns at this site, implying that aggregated phenology explains the larger scale remotely observed patterns. This work significantly reconciles current controversies about satellite-detected Amazon phenology, and improves our use of satellite observations to study climate–phenology relationships in the tropics.
Journal Article
Evolutionary conservation genetics
Conservation genetics focuses on understanding the role and requirement of genetic variation for population persistence. However, considerable debate now surrounds the role of genetic factors (as opposed to non-genetic factors such as habitat destruction, etc.) in population extinction, and a synthesis is now timely. Can extinction be explained by habitat destruction alone or is lack of genetic variation a part of the explanation? The book reviews the arguments for a role of genetics in the present biodiversity crisis. It describes the methods used to study genetic variation in endangered species and examines the influence of genetic variation in the extinction of species. To date, conservation genetics has predominantly utilized neutral genetic markers, e.g., microsatellites. However, with the recent advances in molecular genetics and genomics it will soon be possible to study ‘direct gene action’, following the fate of genetic variation at the level of DNA, through expression, to proteins in order to determine how such phenotypes fare in populations of free living organisms. This book explores these exciting avenues of future research potential, integrating ecological quantitative genetics with the new genome science. It is now more important than ever that we ask relevant questions about the evolutionary fate of endangered populations throughout the globe and incorporate our knowledge of evolutionary processes and the distribution of genetic diversity into effective conservation planning and action.
eBook
GeneFishing to reconstruct context specific portraits of biological processes
Rapid advances in genomic technologies have led to a wealth of diverse data, from which novel discoveries can be gleaned through the application of robust statistical and computational methods. Here, we describe GeneFishing, a semisupervised computational approach to reconstruct context-specific portraits of biological processes by leveraging gene–gene coexpression information. GeneFishing incorporates multiple high-dimensional statistical ideas, including dimensionality reduction, clustering, sub-sampling, and results aggregation, to produce robust results. To illustrate the power of our method, we applied it using 21 genes involved in cholesterol metabolism as “bait” to “fish out” (or identify) genes not previously identified as being connected to cholesterol metabolism. Using simulation and real datasets, we found that the results obtained through GeneFishing were more interesting for our study than those provided by related gene prioritization methods. In particular, application of GeneFishing to the GTEx liver RNA sequencing (RNAseq) data not only reidentified many known cholesterol-related genes, but also pointed to glyoxalase I (GLO1) as a gene implicated in cholesterol metabolism. In a follow-up experiment, we found that GLO1 knockdown in human hepatoma cell lines increased levels of cellular cholesterol ester, validating a role for GLO1 in cholesterol metabolism. In addition, we performed pantissue analysis by applying GeneFishing on various tissues and identified many potential tissue-specific cholesterol metabolism-related genes. GeneFishing appears to be a powerful tool for identifying related components of complex biological systems and may be used across a wide range of applications.
Journal Article
Life's engines : how microbes made Earth habitable
\"For almost four billion years, microbes had the primordial oceans all to themselves. The stewards of Earth, these organisms transformed the chemistry of our planet to make it habitable for plants, animals, and us. Life's Engines takes readers deep into the microscopic world to explore how these marvelous creatures made life on Earth possible--and how human life today would cease to exist without them. Paul Falkowski looks \"under the hood\" of microbes to find the engines of life, the actual working parts that do the biochemical heavy lifting for every living organism on Earth. With insight and humor, he explains how these miniature engines are built--and how they have been appropriated by and assembled like Lego sets within every creature that walks, swims, or flies. Falkowski shows how evolution works to maintain this core machinery of life, and how we and other animals are veritable conglomerations of microbes. A vibrantly entertaining book about the microbes that support our very existence, Life's Engines will inspire wonder about these elegantly complex nanomachines that have driven life since its origin. It also issues a timely warning about the dangers of tinkering with that machinery to make it more \"efficient\" at meeting the ever-growing demands of humans in the coming century.\"--Jacket.
Book
Deep Sequencing Reveals Novel MicroRNAs and Regulation of MicroRNA Expression during Cell Senescence
In cell senescence, cultured cells cease proliferating and acquire aberrant gene expression patterns. MicroRNAs (miRNAs) modulate gene expression through translational repression or mRNA degradation and have been implicated in senescence. We used deep sequencing to carry out a comprehensive survey of miRNA expression and involvement in cell senescence. Informatic analysis of small RNA sequence datasets from young and senescent IMR90 human fibroblasts identifies many miRNAs that are regulated (either up or down) with cell senescence. Comparison with mRNA expression profiles reveals potential mRNA targets of these senescence-regulated miRNAs. The target mRNAs are enriched for genes involved in biological processes associated with cell senescence. This result greatly extends existing information on the role of miRNAs in cell senescence and is consistent with miRNAs having a causal role in the process.
Journal Article
Taxonomic Tapestries
This volume explores the complexity, diversity and interwoven nature of taxonomic pursuits within the context of explorations of humans and related species. It also pays tribute to Professor Colin Groves, whose work has had an enormous impact on this field. Recent research into that somewhat unique species we call humankind, through the theoretical and conceptual approaches afforded by the discipline of biological anthropology, is showcased. The focus is on the evolution of the human species, the behaviour of primates and other species, and how humans affect the distribution and abundance of other species through anthropogenic impact. Weaving together these three key themes, through the considerable influence of Colin Groves, provides glimpses of how changes in taxonomic theory and methodology, including our fluctuating understanding of speciation, have recrafted the way in which we view animal behaviour, human evolution and conservation studies.
eBook
Marine connectivity dynamics: clarifying cosmopolitan distributions of marine interstitial invertebrates and the meiofauna paradox
Many interstitial species were first described as widely distributed, often cosmopolitan or amphi-oceanic, contrasting with descriptions of a sedentary life style and the general absence of pelagic dispersal stages. These inconsistencies became known as the “meiofauna paradox”. In this review, we present a literature review investigating these inconsistencies and address the assumptions of the meiofauna paradox. We break the paradox down to two aspects including species distribution and dispersal. Focusing on distribution, we demonstrate that wide distributions are seldom given and false records likely stem from biological phenomena like stasis or recent speciation. These phenomena account for morphological similarity, ultimately represented by the pronounced occurrence of cryptic species with restricted distribution ranges. Additionally, taxonomic artefacts such as the erroneous application of taxonomic keys contribute to the report of widely distributed species. Considering dispersal, we point out the mismatch between traditional assumptions of meiofaunal sedentarism and growing experimental and empirical evidences suggesting higher dispersal potential. These evidences include not only indications for dispersal by pelagic stages, but further consider ecological and life-history traits in shaping distribution ranges. We conclude that the meiofauna paradox sensu stricto most likely does not exist and provide a roadmap for future research, suggesting a focus on morphological similarity and marine connectivity. Meiofaunal research should concentrate on evolutionary factors resulting in morphological similarity, improving the taxonomic resolution of species complexes and conducting more sophisticated experimental experiments to meiofaunal dispersal. In all cases, meiofaunal research will benefit from high-throughput sequencing such as genome scanning approaches, metagenomics or metatranscriptomics.
Journal Article